1. Field of the Invention
The present invention relates to a plasma processing apparatus for generating homogeneous plasma over a wide area through the control of microwaves by using a variable coupler.
2. Background Art
In the semiconductor manufacturing process, various types of plasma processing are performed by use of a plasma processing apparatus using microwave. These processes include thin film formation by plasma chemical vapor deposition, plasma dry etching, etc. To unify and homogenize such plasma processing, microwave is controlled.
The Patent Document 1 describes a microwave processing apparatus, in which microwave generated from a magnetron is introduced into a vacuum process chamber via an isolator, a directional coupler and an impedance control system. In this microwave processing apparatus, length of microwave propagation route from the magnetron to the vacuum processing chamber is adjusted to achieve impedance matching or impedance.
[Patent Document 1] JP-A-1997-64611